/*
给按钮加个泡泡的粒子效果 来自掘金
按钮背景颜色,粒子颜色,按钮阴影颜色,按钮圆角
*/
@mixin bubble($back-color:#ff0081, $bubbleColor:#ff0081, $showdowColor:#e91e63, $radius:5px) {
  background-color: $back-color;
  color: #fff;
  border-radius: $radius;
  border: none;
  cursor: pointer;
  position: relative;
  box-shadow: 0 2px 20px rgba($showdowColor, .5);
  outline: 0;
  transition: transform ease-in 0.1s, background-color ease-in 0.1s, box-shadow ease-in 0.25s;

  &::before {
    position: absolute;
    content: '';
    left: -2em;
    right: -2em;
    top: -2em;
    bottom: -2em;
    pointer-events: none;
    transition: ease-in-out .5s;
    background-repeat: no-repeat;
    background-image: radial-gradient(circle, $bubbleColor 20%, transparent 20%),
      radial-gradient(circle, $bubbleColor 20%, transparent 20%),
      radial-gradient(circle, $bubbleColor 20%, transparent 20%),
      radial-gradient(circle, $bubbleColor 20%, transparent 20%),
      radial-gradient(circle, $bubbleColor 20%, transparent 20%),
      radial-gradient(circle, $bubbleColor 20%, transparent 20%),
      radial-gradient(circle, $bubbleColor 20%, transparent 20%),
      radial-gradient(circle, $bubbleColor 20%, transparent 20%),
      radial-gradient(circle, $bubbleColor 20%, transparent 20%),
      /*  */
      radial-gradient(circle, $bubbleColor 20%, transparent 20%),
      radial-gradient(circle, $bubbleColor 20%, transparent 20%),
      radial-gradient(circle, $bubbleColor 20%, transparent 20%),
      radial-gradient(circle, $bubbleColor 20%, transparent 20%),
      radial-gradient(circle, $bubbleColor 20%, transparent 20%),
      radial-gradient(circle, $bubbleColor 20%, transparent 20%),
      radial-gradient(circle, $bubbleColor 20%, transparent 20%);
    background-size: 10% 10%, 20% 20%, 15% 15%, 20% 20%, 18% 18%, 10% 10%, 15% 15%, 10% 10%, 18% 18%,
      15% 15%, 20% 20%, 18% 18%, 20% 20%, 15% 15%, 10% 10%, 20% 20%;
    background-position: 18% 40%, 20% 31%, 30% 30%, 40% 30%, 50% 30%, 57% 30%, 65% 30%, 80% 32%, 15% 60%,
      83% 60%, 18% 70%, 25% 70%, 41% 70%, 50% 70%, 64% 70%, 80% 71%;
    animation: bubbles ease-in-out .75s forwards;
  }

  &:active {
    transform: scale(0.95);
    background-color: $bubbleColor;
    // TODO 这里要换成 showdowColor
    box-shadow: 0 2px 25px rgba(233, 30, 99, 0.5);
  }

  &:active::before {
    animation: none;
    background-size: 0;
  }

  @keyframes bubbles {
    0% {
      background-position: 18% 40%, 20% 31%, 30% 30%, 40% 30%, 50% 30%, 57% 30%, 65% 30%, 80% 32%, 15% 60%,
        83% 60%, 18% 70%, 25% 70%, 41% 70%, 50% 70%, 64% 70%, 80% 71%;
    }

    50% {
      background-position: 10% 44%, 0% 20%, 15% 5%, 30% 0%, 42% 0%, 62% -2%, 75% 0%, 95% -2%, 0% 80%,
        95% 55%, 7% 100%, 24% 100%, 41% 100%, 55% 95%, 68% 96%, 95% 100%;
    }

    100% {
      background-position: 5% 44%, -5% 20%, 7% 5%, 23% 0%, 37% 0, 58% -2%, 80% 0%, 100% -2%, -5% 80%,
        100% 55%, 2% 100%, 23% 100%, 42% 100%, 60% 95%, 70% 96%, 100% 100%;
      background-size: 0% 0%;
    }
  }
}